Classic preservation methods, for example in an autoclave, cause overpasteurization or oversterilization in the treated products by long heating times and subsequent balancing and holding times, and damage heat-sensitive ingredients, for example colorants and vitamins. Further restrictions consist in a required minimum content of liquid in the product, a maximum size of solid product ingredients, and restricted pack sizes.
As an alternative, it was therefore suggested, for example in GB 1 354 359, to fill a package can consisting of an insulating cylindrical envelope, a metal bottom and a metal lid, with product, to seal it hermetically, and to apply a voltage between the lid and the bottom to sterilize the product. Due to quicker heating and cooling, sensitive ingredients and thus the color, taste and structure of the product are to be better preserved. This method, however, could not yet be economically realized on a large scale.